The overall problem with which dyslexia patients are faced is to relate sound to the adequate letter. The dyslexic individual who does not automatically achieve developed phonological awareness will lack the fundamental requirements for learning to read and write. He/she will have difficulties in recognising and defining speech sounds. Several studies in this respect support the method involving presentation of the sound by visualisation thereof. In addition, dyslexia is often linked with the possession of creative abilities manifesting themselves for instance in excellent visual perception. The method of creating a link between sound and letter by means of visualisation therefore offers a pedagogical possibility of employing the own resources of the dyslexic individual.
However, the method could also advantageously be used in many other connections, among them for elementary school pupils having a particular need for phonological training, for instance pupils having concentration difficulties. The method is equally useful with respect to individuals who have impaired hearing or are deaf.
Another possible use of the method is for the rehabilitation of individuals in need of rehabilitation following a stroke or an accident to improve their abilities of speech, reading and writing.
Another possible field of use is that of language training, in which field the method may facilitate the learning of new languages.
The invention relates to a device according to which the above method may be practised automatically, allowing the student to use the device essentially on his own for practising purposes.
Such automated speech teaching devices are previously known, e.g. from U.S. Pat. No. 2,533,010. The device described in that publication comprises a sound-recording microphone registering the sound produced by the user. The sound is then presented in graphic forms frequency curves displayed on a screen. Simultaneously, a cross section through the oral cavity and a picture of the lips are display to show how the speech organs preferably should be positioned and moved to produce a word, also displayed on the screen. A curve representing a teacher's standard solution also is displayed, allowing the user to compare the curve produced by him with the standard.
The disadvantages of this solution are, however, that it is comparatively inconvenient to use. It does not allow the user to decide for himself what words or phonemes he wishes to practise. In addition, the link between the curves and the image of the speech organs is difficult to interpret by the user. At best, the user may register the existence of a difference between the curve produced by himself and the teacher-produced one, but he is offered no help as to how to change the sound production in order to improve the sound. On the whole, the prior-art device generally is a poor instructor of how to produce the sound, i.e. where in the oral cavity that the sound is to be generated, and how the formation of the sound should be done. Other disadvantages connected with this prior-art device are that it is large and space-requiring.
Also WO 94/17508 discloses a device comprising a microphone for recording sound, a computer for transforming sound into a curve, and a screen for displaying the curve thus obtained, a curve representing a teacher's solution and the discrepancy between the two curves. This device is smaller and more manageable than the previous one. However, also in this case the user is not informed of how the sound production/formation is to take place or what changes are required in order to reduce any differences that may exist between the user-produced curve and that of the teacher's solution.
The document GB 2 198 871 A, finally, discloses a device similar to those described above, with the difference that it allows the user to decide for himself and to have influence on which phonemes he wishes to practise or how they are to be combined to form various words. This is achieved by the user indicating a letter or a combination of letters by means of an operating means. The above-mentioned drawbacks are, however, found also in this device.